Leaching chambers of a type applicable to the present invention comprise molded thermoplastic articles having arch shape cross sections. Having open bottoms and perforated sidewalls, they are used for dispersing wastewater beneath the surface of the earth. See for instance U.S. Pat. Nos. 5,511,903, 5,401,116, and 4,759,661. As indicated in U.S. Pat. No. 5,017,041 and as well-known in commerce, wastewater or other water to be dispersed in medium is flowed to a leaching chamber by means of piping. Most commonly, and of interest in this application, the water is flowed by gravity through a 2 to 4 inch diameter polyethylene pipe. The water typically enters the chamber through an endplate, also called an end cap, having a suitable size hole for the inflow pipe. The water then flows from the chamber downwardly and sideways, through the perforated sidewalls and into the surrounding medium. It is often a desire or regulatory requirement that the inflow pipe invert (i.e., the bottom of the pipe interior) at the point of chamber entry be at a certain elevation relative to the base of the chamber, to achieve most effectiveness for the perforated walls and to enable storage of a certain large water volume within the chamber.
A typical prior art endplate, made of blow molded polyethylene, is shown in FIGS. 7 and 11 of Nichols U.S. Pat. No. 5,017,041. The cutout at the top of the endplate cooperates with the subarch at the top of the chamber, to provide high invert elevation. Some prior art endplates have molded circular grooves, so the installer can select the elevation and diameter for pipe entry. But the upper height limit is determined by the size of the end plate.
Sometimes the invert elevation which is needed, because of the particular chamber design or imposed installation criteria, is higher than that which allowed by use of a simple flat plate closure at the end of the chamber. That kind of need has been addressed in various ways in the prior art. One approach is shown in U.S. Pat. No. 5,839,844 of Nichols and Coppes, namely, a flat plate type end cap has a duct for receiving the inflow pipe. The duct is bent upwardly on a zigzag path, i.e., vertically and then horizontally. A disadvantage of the endplate with integral duct is that end caps having different inflow pipe invert elevations have to be made and stocked, since it is also a desire to raise the inlet pipe elevation as little as possible when that is needed, to help comply with requirements of minimum amounts of soil overlying the piping. And the bent duct approach can be infeasible when the end cap has a more complicated configuration, which provides the option of a variety of different connection points. See, for instance, the end cap of patent application Ser. No. 10/677,771 of Burnes et al., referred to below.
Another option for raising the invert level, used is the past, involves one or more pipe fittings, e.g., elbows and couplings. Typically, an inflow pipe stub runs at an upward incline angle from the hole in the article and is connected with the rest of the inflow piping by means of an elbow, such as a 22.5 degree elbow. While effective, cutting and fitting of the piping in the field is needed. Sometimes the environment is difficult; and there are labor cost increases.
Thus, there is a need for improvement in the way in which piping can be connected to leaching chambers and other articles, when the elevation of the inlet pipe invert dictated by the article design is too low.